Cam forming attachment



M y 1950 J. A. SHEPHARD 2,597,547

CAM FORMING ATTACHMENT Filed Sept. 16, 1946 3 Shee-ts$heet 1 James A. She Sh y 1950 J. A. SHEPHARD 2,507,547

CAM FORMING ATTACHMENT Filed Sept. 16, 1946 3 SheetsSheet 2 ZV 26 Fig.4 1|

James A; Shephard y 1950 J. A. SHEPHARD 2,507,547.

CAM FORMING ATTACHMENT Filed Sept. 16, 1946 :5 Sheets-Sheet s Q 1.1 gwue/wbo b 5 J mes A. Shep/ward 7 fl n 2% SHOW enin the lead bar 50 at any adjusted angle to its carrier 28. The arcuate slot 55 is such as to permit the lead bar 50 to be fixed in a position parallel to the slideway l2 to its carrier 28 or at a desired limited angle thereto. When the lead bar is at any angle to slideway l2, it will be apparent that rotation of the hand crank 31 will cause this lead bar 50 to ride over the shoe 4! and cause the bridge piece 40 to move the carrier 4 and its parts along the slideway l3 at right angles to the movement of the carrier 28. It will, hence, be apparent that rotation of the screw 3| will rotate the gear I! through its rack 55, and when the lead bar 59 is at any angle, its slideway l2 will also cause the gear I! to be moved along the slideway l3 and at right angles through the slideway l2, thus causing the Work piece 23 mounted thereon to be given a controlled rotary as well as translatory motion against a milling cutter 5? having a projecting finger 58 receivable in a guide race 60 journaled in a bracket 6| adjustably mounted by means of screws 62 on the base plate I 5. By appropriately fixin the angle of the lead bar 50, a desired spiral can thus be cut into the edge of the work piece 23.

In order to accurately set the angle of the lead bar 56 so as to accurately provide the desired cut in the work piece, there is provided a micrometer 63 having a measuring finger 6 extending through a cross block 65. A micrometer bracket 66 is secured to the carrier 28 by screws 61. This bracket 85 has upstanding walls between which the micrometer block 65 maybe inserted with the micrometer 63 extending to one side thereof and the micrometer measuring finger 64 extending to the other side to contact the recessed wall '19 of the lead bar 50. When the micrometer has been appropriately set, the lead bar 55 is rotated about its pivot bolt 53 until its recessed wall l contacts the end of the micrometer measuring finger 6 and then the nut 56 is tightened to lock it in place. The micrometer may be appropriately graduated so as to give a direct reading. However, conventional graduation of a micrometer may be used. The following formula should be used when setting the micrometer having the conventional graduations:

Rise X 100 m Micrometer reading Rise X360 W Mic. readin The entire formula is based on the relation between one complete turn of the cam 23 being cut, and the distance the inclined guide bar 56 (or any other means of moving the cam into or away from the cutter) travels, during that one complete turn of the cam 23, and the proportion of that travel of the guide bar 50 (or other means) at which the micrometer finger 64 is located from the point of pivot of the guide bar 50.

In this construction of attachment the formula is based on the relation of the length of the pitch circle of the gear I? moved by the rack l5 (the pitch circle being the same length as the travel of the guide bar), and the distance, in a parallel line, to the rack l5, from the point of pivot 5| of the guide bar 56 to the point of contact of the micrometer finger 64 and guide bar 50, that point of contact being made by the micrometer 63 mounted at right angle to a parallel line to the rack I5, and a line running through the center of point of pivot 5| and parallel to the guide way of the guide bar. In this attachment it is A the circular pitch, so, therefore, the formula reads:

Rise X No. spaces X 2 Example: A lobe with /2 inch rise in 25 spaces.

'-" gg =1.000 Mic. reading The micrometer 63 is a standard type graduated in .001 of an inch.

A lip guard 69 and an oiler pad appropriately shaped is attached to the end of the carrier M to protect the slideway |3 from the milling cuttings, While a sheet metal guard 75, shown in dot-dash in Fig. 1, protects the teeth of gear I! and rack |5 from the cuttings.

In operation, the cam forming attachment H] of this invention may be attached to the bed 12 of a drill press or similar available machine by the usual attaching bolts 13 and fingers '14. Before fastening the nut 13, however, the lead bar 50 will be set at the appropriate angle by means of the micrometer 63, as above described, and the milling cutter 51 will be mounted for rotation by the drill press and will have its finger 58 in the guide race 60. The Work piece 23 previously roughed out as much as desirable in any conventional manner, is fastened in position by the stud 2d and U washer 25. Then with the milling cutter being rotated by the drill press the hand crank 31 will be slowly rotated, and through actuation 0f the nut 30, the carrier 28, the rack I5 and the gear H, the work piece 23 will be caused to rotate simultaneously as it moves against the rotating milling cutter 51 thus forming the desired cam lobe in the work piece. By appropriate setting of the lead bar any desired cams or lobes may be formed, reverse lobes, of course, being formed by merely turning the work piece upside down. After the cam has been cut, it will be finished or hardened in the usual manner.

Other modifications and changes in the number and arrangement of the parts may be made by those skilled in the art without departing from the nature of this invention within the scope of what is hereinafter claimed.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. A cam forming device comprising a work piece mounting apparatus comprising means for rotating the work piece and for translating the work piece simultaneously, said means including a base plate, a pair of slideways on said base plate at right angles to each other, a carrier slidably supported in each slideway, a work piece carrying gear journaled on one carrier, a rack meshed with said gear, a third slideway slidably supporting said rack on said gear carrier, means extending from the other carrier and slidably engaging said rack, an angularly adjustable lead bar pivotally secured on said other carrier, a bridge piece extending from said gear and rack carrier, a trackway in said lead bar cooperating with said =Mic. reading bridge piece, and means for translating said lead bar carrier.

2. A cam forming device comprising a work piece mounting apparatus comprising means for rotating the work piece and for translating the work piece simultaneously, said means including a base, a pair of tracks on said base forming a T to each other, a carrier slidably supported in each track, a work piece carrying gear journaled on one carrier, a rack meshed with said gear, a

slideway on said gear carrier, said rack being mounted in said slideway, arms extending from the other carrier and slidably abutting both ends of said rack, an angularly adjustable lead bar on said other carrier, a bridge piece extending from said gear and rack carrier, an inverted trackway in said lead bar cooperating with said bridge piece, and means for translating said lead bar carrier over said bridge piece.

JAMES A. SHEPHARD.

REFERENCES GITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,082,310 Turnepseed June 1, 1937 2,366,993 Antos Jan. 9, 1945 2,386,973 Mieth Oct. 16, 1945 2,392,606 Maddox Jan. 8, 1946 

